Mounting disks through TB hub super slow
I have a CalDigit TS3+ Thunderbolt 3 hub that is connected to 2 USB drives (spinning backup drives, not SSDs), a monitor and Ethernet. I use it with 2 different Macs, each running Ventura. One Mac is a 2020 M1 Air, the other is a 2019 MacBook Pro (Intel). The 2 USB drives are used for Time Machine on each Mac, respectively. One is encrypted (for work), the other is not. This scheme has worked well for several years.
Recently, these USB drives take FOREVER to mount upon connection to the hub - as long as 20 minutes. During that time, the Mac may experience 5 to 10 seconds of complete freeze - all screen animations stop, the mouse won't move, etc. This occurs on BOTH MACS, so it's not an Apple Silicon thing. It's something shared.
I've checked the drives via Disk Utility and run First Aid, they appear to be fine. Once mounted, they work perfectly. What else should I look at, fellow Mac people?
MacBook Air (M1, 2020)